Field
Embodiments described herein relate to the fabrication of integrated circuits. More particularly, embodiments described herein relate to a method and apparatus for processing a substrate that improve electronmigration (EM) between a conductive material and a dielectric material.
Description of the Related Art
Integrated circuits have evolved into complex devices that can include millions of components (e.g., transistors, capacitors and resistors) on a single chip. The evolution of chip designs continually requires faster circuitry and greater circuit densities. The demand for greater circuit densities necessitates a reduction in the dimensions of the integrated circuit components.
As the dimensions of the integrated circuit components are reduced (e.g., sub-micron dimensions), the materials used to fabricate such components contribute to the electrical performance of such components. For example, low resistivity metal interconnects (e.g., aluminum and copper) provide conductive paths between the components on integrated circuits.
One method for forming vertical and horizontal interconnects is by a damascene or dual damascene method. In the damascene method, one or more dielectric materials, such as the low k dielectric materials, are deposited and pattern etched to form the vertical interconnects, i.e. vias, and horizontal interconnects, i.e., lines. Conductive materials, such as copper containing materials, and other materials, such as barrier layer materials used to prevent diffusion of copper containing materials into the surrounding low k dielectric, are then inlaid into the etched pattern. Any excess copper containing materials and excess barrier layer material external to the etched pattern, such as on the field of the substrate, are then removed and a planarized surface is formed by chemical mechanical polish (CMP). A dielectric layer, such as an insulation layer or barrier layer is formed over the copper feature for subsequent processing, such as forming a second layer of damascene structures.
To prevent the conductive material diffusion across the boundary regions, barrier and capping layers may be deposited over the conductive material to contain the conductive material. One interface that such diffusion may occur is between the conductive material and the dielectric barrier layer formed over the conductive material. Therefore, an improved barrier layer is needed to improve EM reliability.